Folding knife



FIG. 1 is a right side elevational view of a folding knife showing mynew design;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear end elevational view thereof; and

FIG. 6 is a front end elevational view thereof.

The ornamental design for a folding knife, as shown and described.